1. Field of the Invention
The present invention relates to a method of making a component of a bicycle, and more particularly to a method of making the rear hubs of a bicycle.
2. Description of the Prior Art
Hub is an important component disposed in the center of a wheel of a bicycle, and the hub is generally in the form of a hollow pipe that is formed at either end thereof with a circular hub flange, and in the hub flange are annularly formed a plurality of through holes for insertion of spokes.
U.S. Pat. No. 4,998,344 discloses a method for manufacturing a hub, which comprises the following steps: rotary swaging a section of a tube into a rough shape of a hub; cutting the swaged portion from the tube; and squeezing both ends of the swaged portion by a right mold and a left mold so as to form a hub. However, this method of manufacturing a hub still has the following shortcomings that need to be improved:
Firstly, the length of the resultant hub usually exceeds the maximum tolerance because of the factors of the molding tolerance and the length tolerance of the work piece.
Secondly, during the swaging process, the radial dimension of the hub often deviates from the preset value. If the hole of the hub is too large, then the axle cannot be firmly positioned in the hub, and if the hole of the hub is too small, it will be difficult to assemble the axle into the hub.
Thirdly, the after-swaging hub must be trimmed prior to squeezing process due to the length of the resultant hub usually exceeds the maximum tolerance as mentioned above, and the hub after squeezing should also be subjected to a trimming process for the same reason.
Fourthly, the hub after squeezing is still not a finished product because it has to be subjected to chamfering, punching, etc, otherwise spokes and shaft cannot be assembled.
Other methods for making bicycle hub, such as disclosed in U.S. Pat. Nos. 1,754,922, 1,928,911, also have the same disadvantages as mentioned above, namely, after each step is done and prior to the next step is performed, it requires an extra trimming process to trim the work piece, so the steps are not performed consecutively, which adversely affects the production efficiency.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.